Corner valve for plastic bags

ABSTRACT

One corner of a plastic bag is provided with an inwardly extending triangular fold. A rectangular insert of plastic having a reverse fold along one edge thereof is folded along a center line transverse to the reversely folded edge and secured in the triangular fold at the corner of the bag with the side edges of the insert which are perpendicular to the reverse fold being flush with the top edges of the bag. The top edges of the bag and the side edges of the rectangular insert are secured together so that the insert defines a sleeve adapted to fit over the end of a cylindrical filling spout. When the bag is completely filled the sleeve and top edges of the bag will be flattened out in a substantially horizontal plane and the reversely folded flap on the insert can be pulled out and re-folded over the top of the bag to close off the sleeve to substantially prevent the loss of the contents of the bag while permitting the escape of air from the interior of the bag.

United States Patent Henderson July 15, 1975 CORNER VALVE FOR PLASTIC BAGS [75] Inventor: Harold E. Henderson, Tyler, Tex. [57] ABSTRACT 1 1 Assigneel Nafimla] Pisfiners and Chemical One corner of a plastic bag is provided with an in- 'l m New York, wardly extending triangular fold. A rectangular insert [22] Filed: June n, 1974 of plastic having a reverse fold along one edge thereof Appl. No.: 478,421

Primary Examiner-William 1. Price Assistant Examiner-Stephen P. Garbe Attorney, Agent, or Firm-Allen A. Meyer, Jr.

is folded along a center line transverse to the reversely folded edge and secured in the triangular fold at the corner of the bag with the side edges of the insert which are perpendicular to the reverse fold being flush with the top edges of the bag. The top edges of the bag and the side edges of the rectangular insert are secured together so that the insert defines a sleeve adapted to fit over the end of a cylindrical filling spout When the bag is completely filled the sleeve and top edges of the bag will be flattened out in a substantially horizontal plane and the reversely folded flap on the insert can be pulled out and re-folded over the top of the bag to close off the sleeve to substantially prevent the loss of the contents of the bag while permitting the escape of air from the interior of the bag.

4 Claims, 13 Drawing Figures CORNER VALVE FOR PLASTIC BAGS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to plastic bags for receiving bulk products and more specifically to a closable filling valve disposed in one corner of the bag which is otherwise completely closed prior to filling.

2. Prior Art In the past, most plastic bags used for the packaging of bulk products were completely open at one end during the filling of the bag and the top edges of the bag would subsequently be secured together by heat sealing means or the like. Other bags would be partially closed along their top edges leaving only a small opening through which a filler tube would extend and upon the withdrawal of the filler tube the upper edges of the bag would be completely sealed together. In both of these prior art arrangements a certain amount of air would be trapped within the bag after the edges were sealed so that when a plurality of bags were stacked ballooning of the plastic bags would occur. Such ballooning was considered to be undesirable since under extreme circumstances the force of the air pressure could possibly rupture the plastic bag, especially at the closure thereof. If the bulk material had a substantial grain size such as pine bark chips or the like the bag could be provided with perforations which would be either spaced over the entire surface of the bag or along the closure line to allow air to escape from the interior of the bag.

However, finely divided bulk products such as powdered fertilizer or the like could not be placed in a bag having any perforations since a substantial amount of the bulk product would be lost through the perforations during handling. Therefore, such finely divided bulk products always had to be packaged heretofor in a completely sealed bag which resulted in the aforementioned detrimental ballooning of the bags during handling and stacking. Various schemes have been devised for trying to evacuvate most of the air from the bag prior to scaling the filled bag but none of these have proven to be very successful.

SUMMARY OF THE INVENTION The present invention provides a bag which is extremely suitable for the packaging of practically every conceivable type of bulk products, especially finely divided. powder-like material. The bag is provided with a closable filling spout which will permit the escape of excess air without any substantial loss of the powder product.

The present invention provides a bag having a corner valve into which a conventional horizontally disposed bag filling spout may be inserted and which is provided with a closure flap which may be manually folded over the top of the bag to close the valve subsequent to the filling of the bag and the withdrawal of the spout.

The present invention provides a corner valve for a plastic bag which is comprised ofa rectangular sheet of plastic material having a reverse fold along one edge thereof and which is secured in superposed relation to an inwardly folded triangular bag corner with the side edges of the insert perpendicular to the reverse fold being flush with the top edges of the bag. When the top edges of the bag and the side edges of the insert are sealed together the insert will define a filling sleeve adapted to fit over the end of a conventional horizontally disposed filling spout. After the bag is filled and the spout removed the top portion of the bag will be flattened out in a substantially horizontal disposition and the reverse fold on the insert may be pulled out and folded back over the top of the bag to effectively close the sleeve to prevent the loss of material from the bag while permitting the escape of air therefrom.

The present invention provides a corner valve which is equally compatible with bags having single folded side edges as well as with bags having gusseted side edges.

The foregoing and other object features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of one corner of a plastic bag showing the corner valve in the open condition for the reception of a cylindrical filling spout.

FIG. 2 is a side elevation view of the bag corner in FIG. 1 taken in the direction of the line 2-2 with portions of the bag and valve broken away for the purposes of illustration.

FIG. 3 is a view similar to FIG. 2 but showing the bag in the filled condition with the closure flap in the process of being folded out in the direction of the arrow.

FIG. 4 is a view similar to FIG. 3 showing the flap being folded over the top of the bag in the direction of the arrow.

FIG. 5 is a perspective view of the top corner of the bag showing the corner valve in the closed position.

FIG. 5a is a top plane view of the bag corner shown in FIG. 5.

FIG. 6 is an exploded view of the top portion of a bag and the valve insert prior to secure them together.

FIG. 6a is a top plane view of the arrangement shown in FIG. 6.

FIG. 7 is a perspective view similar to FIG. 6 but showing the valve insert secured to the top corner of the bag.

FIG. 7a is a top plane view of the arrangement shown in FIG. 7.

FIG. 8 is a perspective view of the corner valve arrangement of FIG. 7 as the top edges of the bag and the insert are being secured together.

FIG. 8a is a side elevation view of the finished corner valve arrangement of FIG. 8 prior to filling.

FIG. 9 is a side elevation view of the finished corner valve as used in conjunction with a bag having gusseted side edges.

DETAILED DESCRIPTION OF THE INVENTION The plastic bag to which the corner valve of the pres ent application may be fitted is a standard type of plastic bag utilized for packaging fertilizers, peat moss, mulches, potting soils, powdered or granulated products and the like. The size of the bag may vary considerably and the size of the corner valve can also be varied depending upon the type of filling equipment which will be used to fill the bags. The material and construction of the bag may also vary widely but, for example, in the present application the bag will be constructed from a flattened tubular length of polyethylene film which is heat sealed at one end thereof to define an open ended bag.

The bag shown in FIG. 1 is provided with a corner valve generally designated at 12 and the uppermost edges 14 of the bag have been heat sealed together and covered by in inverted U-shaped sealing strip 16 as is conventional in the bag art. The corner valve 12 of the empty bag 10 in FIG. 1 is spread open to define a cylindrical passage 18 which is adapted to slide over a cylindrical filling spout of a conventional bag filling apparatus. The bag filling apparatus has not been illustrated since it is not a part of the present invention but the filling spout referred to is generally horizontally disposed at the bottom of a hopper and is comprised of an elongated cylindrical tube utilizing a forced air flow or having a screw type feed mechanism therein for forcing the bulk products into the bag. A conventional air vent or passage may be provided in conjunction with the filling spout since it is customary to clamp the valve 12 to the cylindrical filling spout during the filling operation thereby preventing the escape of air between the sleeve and spout.

The corner of the bag to which the valve 12 is applied is folded inwardly to define a triangular flap 20 and the valve 12 is secured partially within the triangular flap with the innermost end thereof extending into the interior of the bag. The dimensions of the flap valve will vary depending upon the diameter and length of the filling spout which is to be used.

The sequence of steps involved in the formation of the corner valve in the plastic bag is best shown in FIGS. 6-80. In FIG. 6 the tubular plastic bag 10 is folded inwardly at one corner to define the triangular flap 20 which is disposed and supported in a substantially horizontal position by a suitable anvil or support surface (not shown). The valve 12 is comprised of a rectangular piece of plastic material 22 which is pro vided with a reversely folded flap 24 along one edge thereof. The flap 24 is then secured to the main sheet 22 by two spaced apart heat seals 26 and 28. The thus formed insert is then placed upon the inwardly folded triangular flap 20 with the flap 24 between the flap 20 and the sheet 22 as best illustrated in FIGS. 6 and 7. The free edge 30 of the flap 24 is spaced outwardly of the free edge 32 of the triangular flap 20 so that when the sheet 22 is secured to the flap 20 adjacent the edge 32 by means of the transverse heat seal 34 the edge 30 of the flap 24 will remain free. The end edges 36 and 38 of the sheet 22 are secured to the edges 14 of the tubular bag 10 by means of heat seals 40 and 42. The heat seals 40 and 42 also secure the end edges of the flap 24 to the edges 36 and 38 of the main sheet 22. The sheet 22 is further secured to the bag 10 by means of heat seals 44 and 46 which are parallel to the end heat seals 40 and 42 and perpendicular to the transverse seal 34. The heat seals 44 and 46 are generally aligned with the heat seals 26 and 28 on the flap but are spaced therefrom. The heat seals 34, 40, 42, 44 and 46 may be performed simultaneously or separately depending upon the heat scaling equipment available.

The sides of the bag 10 are then folded back up into fact-to-face relation best shown in FIG. 8 and the flap 20 and the sheet 22 will be folded about the line 48. The uppermost edges I4 of the bag and the edges 36 and 38 of the valve insert 12 are then secured together by any conventional heat sealing equipment. In the present case, the heat sealing equipment includes the use of a sealing strip 16 which is folded over the top edges of the bag and valve insert and the entire assembly is secured together by heat seal 50 best shown in FIG. 8a. The bag with the corner valve is now completed and ready for filling.

In order to fill the bag the valve insert 12 is formed into a tubular sleeve as best shown in FIG. 1 and placed over the end of a filling spout. When the bag is filled as shown in FIG. 3 with the bulk material 50 the spout is withdrawn and the upper portion of the bag is substantially flattened in a horizontal plane as best shown in FIG. 5. An operator may then reach under the protrud ing portion of the valve insert 12 and grasp the free edge 30 of the flap 24 between the heat seals 26 and 28 pull the flap outwardly in a direction of the arrow 52. With the upper portion of the bag flattened out as shown in FIG. 5 the flap 24 can readily be folded over the top edge of the bag in the direction of the arrow 54 in FIG. 4 to close the valve. The filled and closed bag and valve assembly will then appear as shown in FIG. 5. The flap 24 is securely held in place so that it is next to impossible to accidentally open the valve. The flap will substantially prevent the leakage of any of the bulk material from the bag and still provide a vent passage to the interior of the bag. When the filled bags are stacked on their sides the internal pressure of the material on the sheet 22 of the valve 12 will press the sheet 22 against the top of the bag to further close the valve and make it more difficult for the leakage of bulk materials to occur.

The valve construction described above is equally suitable for use with a gussetted bag as shown in FIG. 9. The only difference between the bag in FIG. 9 and the bag 10 described above resides in the fact that the entire edge 62 of the bag is tucked inwardly along the entire length of the bag prior to the closing the bottom of the bag with a heat sealv In this embodiment the edge 64 of the valve assembly 12' will be sahetantially co-extensive with the edge 66 of the bag ram than recessed as in the previous embodiment.

While the invention has been particularly shown and described with reference to the preferred embodiments thereof it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing the spirit or scope of the invention.

What is claimed is:

l. A corner valve for a bag of the type having two sidewalls joined together along the bottom and two side edges comprising an inwardly folded triangular flap at a top corner of the bag, an insert having a reversely folded flap along one edge thereof, first securing means for holding the reversely folded flap in the folded position with the center portion thereof left free, second securing means for connecting said insert to said triangular flap along a line parallel to and spaced from said reversely folded flap. said reversely folded flap being disposed in face-to-face relation with said triangular flap between said second securing means and the adjacent side edge of said bag. the side edges of said insert perpendicular to the reversely folded flap being disposed flush with the top edges of the bag and third securing means for sealing the top edges of the bag and the side edges of the insert together whereby said insert defines a valve filling sleeve adapted to be closed by pulling out said reversely folded flap and re-folding it over the sealed side edges of the insert after the bag is folded.

the insert.

4. A corner valve as set forth in claim 2 wherein the side edges of said bag are folded inwardly along the entire length thereof with the folded edge of said insert being co-extensive therewith. 

1. A corner valve for a bag of the type having two sidewalls joined together along the bottom and two side edges comprising an inwardly folded triangular flap at a top corner of the bag, an insert having a reversely folded flap along one edge thereof, first securing means for holding the reversely folded flap in the folded position with the center portion thereof left free, second securing means for connecting said insert to said triangular flap along a line parallel to and spaced from said reversely folded flap, said reversely folded flap being disposed in face-to-face relation with said triangular flap between said second securing means and the adjacent side edge of said bag, the side edges of said insert perpendicular to the reversely folded flap being disposed flush with the top edges of the bag and third securing means for sealing the top edges of the bag and the side edges of the insert together whereby said insert defines a valve filling sleeve adapted to be closed by pulling out said reversely folded flap and re-folding it over the sealed side edges of the insert after the bag is folded.
 2. A corner valve as set forth in claim 1 wherein said bag and said insert are of plastic material and all of said securing means are heat seals.
 3. A corner valve as set forth in claim 2 wherein said first securing means is comprised of a pair of spaced apart heat seals extending transversely of said reversely folded flap and spaced inwardly from the side edges of the insert.
 4. A corner valve as set forth in claim 2 wherein the side edges of said bag are folded inwardly along the entire length thereof with the folded edge of said insert being co-extensive therewith. 